نتایج جستجو برای: soil seed bank classification

تعداد نتایج: 795075  

1999
Charles B. Halpern Shelley A. Evans Sarah Nielson

During early stand development, coniferous forests of the coastal Pacific Northwest commonly pass through a period of dense shade and intense competition during which the abundance and diversity of understory plants decline dramatically. In young, managed forests, silvicultural thinning has been proposed to enhance the structural and floristic diversity of the understory. Although germination o...

2006
X. Zhan L. Li W. Cheng

The landscapes of Inner Mongolia are widely known for the vast Stipa krylovii steppes. However, overgrazing and other improper land uses have extensively degraded the Stipa krylovii steppe ecosystem in recent decades. Knowledge about the soil seed banks and the remaining vegetation in these damaged ecosystems is crucial for guiding the restoration efforts. Using a germination method, this study...

2005
I. Caballero J. M. Olano A. L. Luzuriaga A. Escudero

Seed banks play a crucial role in arid plant communities because they confer stability and longterm persistence. However, seed banks have high temporal and spatial variability, with dramatic changes in density and composition. The aim of this study was to test whether seasonal change affected seed bank community structure and spatial pattern. Moreover, we wanted to know if the effect driven by ...

Journal: :American journal of botany 2005
José L Espinar Ken Thompson Luis V García

The density of soil seed banks is normally highest at the soil surface and declines monotonically with depth. Sometimes, for a variety of reasons, peak density occurs below the surface but, except in severely disturbed soils, it is generally true that deeper seeds are older. In seasonally dry habitats that develop deep soil cracks during the dry season, it is possible that some seeds fall down ...

Journal: :Acta biologica Hungarica 2010
G Koncz Mária Papp P Török Zs Kotroczó Zs Krakomperger G Matus B Tóthmérész

We studied the potential role of seed bank in the dynamics of the understorey in a turkey oak-sessile oak forest (Querceteum petraeae-cerris) in Hungary. We used long-term records of the herb layer (1973-2006) and the seed bank composition of 2006 to assess the role of seed bank in the regeneration of herb layer. The total cover of herb layer decreased from 22% (1973) to 6% (1988), and remained...

2013
JAMES W. DALLING

Seed limitation, defined as the failure of seeds to arrive at sites favorable for recruitment, may be a critical force structuring plant communities. When seed limitation is strong, interspecific competition is reduced, and competitive exclusion may be slowed to the extent that diversity can be maintained through speciation and migration. In mature tropical forests, seed limitation may be espec...

2007
Elizabeth A. Allen Robert S. Nowak

As pinyon–juniper (specifically, Pinus monophylla and Juniperus osteosperma) woodlands in the western United States increase in distribution and density, understory growth declines and the occurrence of crown fires increases, leaving mountainsides open to both soil erosion and invasion by exotic species. We examined if the loss in understory cover that occurred with increasing tree cover was re...

2018
Wenting Liu Tianle Wang Shuang Zhang Lijun Ding Zhijun Wei

Seed germination plays an important role in determining the composition and regeneration of plant populations (Stipa breviflora). However, the influencing factors and strategies employed for seed germination in desert grasslands under grazing remain unknown. Therefore, in this study, the reproductive allocation, seed density, seed properties, and corresponding seed germination rates of S. brevi...

2002
PABLO E. VILLAGRA LUIS MARONE MARIANO A. CONY

The fate of seeds during secondary dispersal is largely unknown for most species in most ecosystems. This paper deals with sources of seed output of Prosopis flexuosa D.C. (Fabaceae, Mimosoideae) from the surface soil seed-bank. Prosopis flexuosa is the main tree species in the central Monte Desert, Argentina. In spite of occasional high fruit production, P. flexuosa seeds are not usually found...

2007
Shunli Yu Marcelo Sternberg Pua Kutiel Hongwei Chen

Question: Are seed mass and shape related to persistence in the soil seed bank among 54 species of the Israeli flora? Search method: Persistence was determined by soil seed bank investigations in which the fraction of non-germinated viable seeds was regarded as the persistent soil seed bank. When seedling emergence had ceased but before new seeds were shed, all soil from the upper 5 cm of 120 q...

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